a. Field of the Invention
The instant invention is directed toward a catheter and a method for using the catheter for assessment and ablation procedures. In particular, the catheter of the present invention may comprise one or more acoustic transducers for assessment of tissue and/or for assessment of catheter contact with the tissue and/or for tissue ablation procedures.
b. Background Art
It is well known that benefits can be gained by forming lesions in tissue if the depth and location of the lesions being formed can be controlled. In particular, it can be desirable to elevate tissue temperature to around 50° C. until lesions are formed via coagulation necrosis, which changes the electrical properties of the tissue. For example, lesions can be formed at specific locations in cardiac tissue via coagulation necrosis to lessen or eliminate undesirable atrial fibrillation.
Several difficulties can be encountered, however, when attempting to form lesions at specific locations using some existing ablation electrodes. One such difficulty encountered with existing ablation catheters is how to assess the tissue and catheter contact with the tissue. These assessments are not readily determined using conventional fluoroscopy techniques. Instead, the physician assesses the tissue based on his/her experience using the catheter. Such experience only comes with time, and can be quickly lost if the physician does not use the catheter on a regular basis. In addition, when forming lesions in a heart, the beating of the heart further complicates matters, making it difficult to assess and maintain sufficient contact pressure between the catheter and the tissue for a sufficient length of time to form a desired lesion. If the contact between the catheter and the tissue cannot be properly maintained, a quality lesion is unlikely to be created. Likewise, timely feedback assessment and if the lesion cannot be accurately and timely assessed during formation for assessing the tissue and lesion formation is critical to forming quality lesions.